On Wed, 16 Nov 2011 18:44:34 -0500 Jim Rees <rees@xxxxxxxxx> wrote: > Jeff Layton wrote: > > Uhhh, no...EKEYEXPIRED was never passed to userland. The patchset that > added EKEYEXPIRED returns in this codepath also added the code to make > it hang. > > This not a bug, or at least it's intentional behavior. When a krb5 > ticket expires, we *want* the process to hang. Otherwise, people with > long running jobs will often find that their jobs error out > inexplicably when their ticket expires. > > Who decided that? This seems completely wrong to me. If my credentials > expire, I want to get permission denied, not a client hang. In 20 years of > using authenticated file systems I never once wished my process had hung > when my ticket expired. > I proposed it, we discussed it on the list, and Trond and Steve committed the patches necessary to make it happen. This was back in late 2009/early 2010 though, so my memory is a bit fuzzy... > Why should this be any different from any other failure condition? If you > try to open a file that doesn't exist, do you want your process to hang > instead of getting ENOENT, just in case the file magically appears at some > point in the future? > That's different. Not renewing your credentials is often a temporary situation. Kerberos is different than other authentication methods in that you get a ticket only for a period of time, so expired credentials are not a situation that's common with other authentication methods. > This seems a recipe for disaster. Suppose I have a cron job that fires once > a minute, and all those jobs hang waiting for a ticket. I come to work in > the morning and discover I've got 10,000 hung processes. Or not, because my > computer has crashed from resource exhaustion. The previous situation was also a recipe for disaster, and was often cited as a primary reason why people didn't want to deploy kerberized NFS. Having everything fall down and go boom when your ticket expires is not desirable either. I suppose we'll have to agree to disagree on this point. That said, I'm open to sane suggestions however that don't regress the behavior for those users who need to be able to cope with expired tickets. -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
